John 2:23-25

²³Now while [Jesus] was in Jerusalem at the Passover Feast, many people saw the miraculous signs He was doing and believed in His name. ²⁴But Jesus would not entrust Himself to them, for He knew all men. ²⁵He did not need man's testimony about man, for He knew what was in a man.

This passages sets the context for John 3 and the conversation between Jesus and Nicodemus. Consider the following:

• This “belief” was an admiration that God clearly had a purpose for Jesus; His character and impressive activity were noted. Miracles cannot be the root of saving faith. The Gospel must be. Nevertheless, miracles do confirm the truth of the Spirit.
• It was superficial (compare other places in John – 6:25-26, 66; 8:30-31; 10:42; 12, etc.), like the rocky soil from Mark 4 – no root.
• All men are hypocrites. Even hypocrites assent to the Gospel for the simple reason that they don’t want to outright and finally reject it. Jesus knows the heart – Luke 16:15; John 5:42; Acts 15:8; 1 Corinthians 4:5; 14:25; Hebrews 4:12.
• Be fearful – Ecclesiastes 12:13; John 15:10,14; Romans 3:18; Revelation 14:7. Jesus will not accept as His disciples those who are not willing to take up a cross and follow Him.
• Matthew 7:21 – “Not everyone who says to Me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only he who does the will of My Father who is in heaven.” 2 Peter 1:10 – “Therefore, my brothers, be all the more eager to make your calling and election sure.”
• Be humbled entering chapter 3 that Jesus “came to seek and save what was lost” (Luke 19:10).
• John 3 & 4 are similar to Mark 5. There we saw Jairus and the bleeding woman. Here we see Nicodemus and the Samaritan woman. In both encounters, Jesus, upon being asked a question, steers the conversation into deeper spiritual levels that weren’t expected.